1. Field of the Invention
This invention pertains generally to nuclear reactor design, and more particularly to a liquid-fluoride-salt cooled high-temperature nuclear reactor using pebble fuel that achieves high power density.
2. Description of Related Art
Current high temperature reactors, such as the Pebble Bed Modular Reactor (PBMR), use helium as a coolant. Helium-cooled high temperature reactors (HTRs) with prismatic and pebble fuels have been extensively studied and developed, and are well known in the art. Likewise molten fluoride salts were developed in the 1950's as solvents for fluid-fueled nuclear reactors. More recently, reactors using clean liquid fluoride salt as a coolant, and solid prismatic or pebble fuel of similar type to that for helium cooled HTRs, have been proposed
Each of the following publications which provides additional background information and is incorporated herein by reference in its entirety:    P. Bardet, J. Y. An, J. T. Franklin, D. Huang, K. Lee, M. Toulouse and P. F. Peterson, “The Pebble Recirculation Experiment (PREX) for the AHTR,” submitted to Global 2007, Boise, Id., Sep. 9-13, 2007.    M. Fratoni, F. Koenig, E. Greenspan, and P. F. Peterson, “Neutronic and Depletion Analysis of the PB-AHTR,” Global 2007, Boise, Id., Sep. 9-13, 2007.    A. Griveau, F. Fardin, H. Zhao, and P. F. Peterson, “Transient Thermal Response of the PB-AHTR to Loss of Forced Cooling,” Global 2007, Boise, Id., Sep. 9-13, 2007.    P. Bardet, E. Blandford, M. Fratoni, A. Niquille, E. Greenspan, and P. F. Peterson, “Design, Analysis and Development of the Modular PB-AHTR,” 2008 International Congress on Advances in Nuclear Power Plants (ICAPP '08), Anaheim, Calif., Jun. 8-12, 2008.    E. D. Blandford and P. F. Peterson, A Novel Buoyant Shutdown Rod Design for the Passive Reactivity Control of the PB-AHTR,” 4th International Topical Meeting on High Temperature Reactor Technology, Washington, D.C., Sep. 28-Oct. 1, 2008.    R. C. Robertson, 6/71 “Conceptual Design Study of a Single-Fluid Molten-Salt Breeder Reactor,” Chapter 3, “Reactor Primary System,” ORNL-4541, June, 1971.    C. W. Forsberg, P. Pickard and P. F. Peterson, “Molten-Salt-Cooled Advanced High-Temperature Reactor for Production of Hydrogen and Electricity,” Nuclear Technology, 144, pp. 289-302 (2003).    S. J. de Zwann, B. Boer, D. Lathouwers and J. L. Kloosterman, “Static design of a liquid-salt-cooled pebble bed reactor (LSPBR),” Annals of Nuclear Energy 34 (2007) 83-92.    Tallackson, J. R., “Thermal Radiation Transfer of Afterheat in MSBR Heat Exchangers,” ORNL-TM-3145, 3/71.    McWherter, J. R., “Molten Salt Breeder Experiment Design Bases,” ORNL-TM-3177, pg. 26, 11/70.
A practical realization of a liquid-salt cooled high temperature reactor could bring major benefits to nuclear energy by enabling the excellent passive safety and high power conversion efficiency of helium cooled reactors to be achieved, but in a more compact, high power density, low pressure reactor.